Pressure reset mechanism responsive to operation of antidetonant fluid injection system



May 18. 1954 H. A. ALEXANDERSON EFAL 8,

PRESSURE RESET MECHANISM RESPONSIVE TO OPERATION OF ANTIDETONANT FLUID INJECTION SYSTEM Original Filed May 29, 1945 5 Sheets-Sheet l INVENTORS lbwandAAlexandu-saz,

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BY ATTORNEY ET AL 2,678,639 ECHANISM RESPONSIVE. T0 OPERATION y 8, 1954 H. A. ALEXANDERSON PRESSURE RESET M OF ANTIDETONANT FLUID INJECTION SYSTEM Original Filed May 29, 1945 5 Sheets-Sheet 2 lNvENToRs Howard AAIWSOIL Robert 2.11 (42.

ATTORNEY y 18, 1954 H. A. ALEXANDERSON ETAL 2,673,639

PRESSURE RESET MECHANISM RESPONSIVE TO OPERATION OF ANTIDETONANT FLUID INJECTION SYSTEM Original Filed May 29. 1945 5 Sheets-Sheet 3 129 INVENTORS Howa a A. Alex z rsol Robert 2- H115.

ATTORNEY May 18. 9 H. A. ALEXANDERSON ET AL 7 PRESSURE RESET MECHANISM RESPONSIVE TO OPERATION OF ANTIDETONANT FLUID INJECTION SYSTEM Original Filed May 29. 1945 5 Sheets-Sheet 4 Fig-2Q INVENTORS Agexalzdersalz Roberl' Z.

r in ATTORN EY May 18, 1954 H. A. ALEXANDERSON ET AL 2,678,539

PRESSURE RESET MECHANISM RESPONSIVE TO OPERATION OF ANTIDETONANT FLUID INJECTION SYSTEM Original Filed May 29, 1945 5 Sheets-Sheet 5 IN VEN TORS HowqraAAlexandemolz BY Robe/'1' Z. Hague ATTORNEY Patented May 18, 1954 PRESSURE RESET MECHANISM RESPON- SIVE TO OPERATION OF ANTIDETONANT FLUID INJECTION SYSTEM Howard A. Alexanderson, Hohokus, and Robert Z.

Hague, Oradell, N. 1., assignors to Bendix Aviation Corporation, of Delaware Teterboro, N. .l., a corporation Original application May 29, 1945, Serial No.

596,472. Divided and this application December 20, 1950, Serial No. 201,729

26 Claims.

The present application is a division of U. S. application Serial No. 596,472, filed May 29, 1945, by Howard A. Alexanderson and Robert Z. Hague and relates to improved control devices for the power units of aircraft.

An object of the invention is to provide a novel selector linkage arrangement, whereby the datum of the boost control may be selected in accordance with two predetermined programs.

Another object of the invention is to provide a novel control mechanism for selecting in accordance with a first selected program the intake manifold pressure of the aircraft engine, including novel adjustable means for varying the relationship of the intake manifold pressure of the aircraft engine in accordance with a second seiected program brought into operation by a predetermined operating condition.

During operation of the so-called water or anti-knock fluid injection systems for suppressso ing predetonation in internal combustion engines, an increase in the air inlet pressure of the induction system for the engine is permissible and desirable in order that greater engine power may be obtained than when such injection system is i not in operation. Therefore, an object of the invention is to provide a novel regulator responsive to operation of such an injection system for effecting a predetermined increase in the air pressure in the induction system.

Another object of the invention is to provide a pressure reset mechanism in combination with novel means controlled by the pilot for modifying the pressure schedule corresponding to the position of a main control member without changing the setting of the main control member and for nullifying partly or entirely the effect thereon of the reset mechanism.

Another object of the invention is to provide a pilot operated auxiliary control member movable in one direction from a normal position to increase the pressure setting of a regulator to a value above the normal schedule and movable in the opposite direction from anormal position to decrease the pressure setting of the regulator to a value below the normal schedule while the main pilot operated control member remains in a set position and thereby providing pilot operative means to nullify the effect of an independently operable pressure reset mechanism, and to further provide means actuated by the movement of the main control member to certain high or low setting positions for nullifying the effect of the auxiliary control member.

Another object of the invention is to provide a novel linkage arrangement including a bell crank lever operated by the auxiliary control member upon movement in one direction to affect the cam follower of a main control cam in a sense to increase the pressure setting of the regulator relative to a normal schedule and upon movement in an opposite direction to affect the cam follower in an opposite sense to decrease the pressure setting of the regulator relative to the normal schedule and including a pressure reset mechanism acting upon the cam follower to increase th pressure setting under certain operating conditions subject to the overriding eilect of the auxiliary control member.

Another object of the invention is to provide a novel selector plate and a cam follower pivotally connected thereto and normally contactmg the contour surface of a selector cam under the biasing force of a spring which also serves to bias the cam follower into normal contacting relation with the selector plate in which the cam follower is arranged for adjustment out of contacting relation with the cam to vary a selected regulated value in one sense and in which the selector plate is arranged for adjustment out of contacting relation with the cam follower to vary the selected regulated value in an opposite sense and in which an actuating means is provided under control of a condition or fluid pressure responsive means for effecting actuation of the cam follower in the one sense, while pilot operated means may be provided to effect the actuation in the opposite sense to nullify the effect of the first mentioned actuating means.

Another object of the invention is to provide a novel regulator for effecting smooth control throughout the range of operation of the antiknock fluid injection system.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawings wherein one embodiment of the invention is illustrated by way of example.

In the drawings, wherein like reference characters refer to like parts throughout the several views:

Figure 1 is a diagrammatic view of the novel hydraulic control system;

Figure 2 is a diagrammatic view of part of the control mechanism shown in Figure 1;

Figure 2a is a diagrammatic view of a second part of the control mechanism;

Figure 2b is a diagrammatic view of a third part of the control mechanism; and

Figure 3 is an enlarged view of the pressure reset mechanism.

Referring to Figures 1 and 2 there is provided in the present invention a main pilots control lever I, which is connected by a link 2 to an operative control lever 3. As shown in Figure 2, the control lever 3 is keyed to a main control shaft 4 which extends into the main control unit indicated in Figure 1 by the letter A and shown diagrammatically in Figure 2.

Driven by shaft 4 is a propeller pitch governor selector mechanism indicated generally by numeral 5 and including an arm 6 keyed at one end to the shaft 4 and pivotally connected by a link I to an arm 8 rotatablymounted on a shaft 9 eccentrically afiixed to one end of an adjustable pin Ill. The pin 15 is mounted in a casing of the unit A part of which is shown at I DA.

There is further rotatably mounted on the pin 10 an arm II. The arm I I is bent at an acute angle at I2 and pivotally connected to one end of a link [4. The arm I i is connected to arm 8 by an idler shaft l3. The idler shaft l3 extends from points intermediate the opposite ends of arms H and S and is affixed eccentrically to a cam I3A rotatably mounted in an arm H.

The other end of link I 4 is connected to an arm which is keyed to one end of a tubular sleeve l6 rotatably mounted on the shaft 4. The opposite end of the sleeve :6 is keyed to a pulley [1 which as shown in Figure 2 is drivingly connected through lines it to an operating pulley [9 for adjusting a propeller pitch governor control indicated generally by the numeral 23.

The latter propeller pitch governor control may be of a suitable type well known in the art. The same is shown in Figure 1 as being of a type having the operating pulley l9 mechanically connected to a gear 2! and rack 22 for adjusting a governor spring 23 and fly-weight governors 24. The fly-weights 24 are pivotally mounted at one end of a shaft 25 drivingly connected through suitable gear means (not shown) to a drive shaft of an aircraft engine indicated by the numeral 26.

Slidably mounted in the shaft 25 is a valve 27 of conventional type, adjustably positioned under tension of the spring 23 and the counteracting biasing force of the centrifugally actuated fly-weights 25. The valve 21 is arranged to control the operation of a piston not shown which controls the pitch of a propeller 28 driven by the engine 26 in a manner well known in the art.

Thus the engine speed or R. P. M. of the engine 26 may be adjusted by varying through the pulley line l8 the tension of the governor spring 23 and the resultant position of the pilot valve 21. Moreover through the propeller pitch selector mechanism indicated by numeral 5 the relationship of pilots control lever i travel to propeller pitch governor drive travel may be modified by adjustment of the eccentric pin IE! to accommodate production variations in the angular travel of propeller governors 20.

The engine 26 also drives through a shaft 30 and a two speed hydraulic coupling 3| 2. supercharger 32.

The coupling 3: includes a gear 33 keyed to the shaft 30 and driving high speed coupling gear 34 and low speed coupling gear 35.

The high speed coupling gear 33 drives through a shaft 36 rotatably supported by a bearing 31 one set of blades 38 of a hydraulic coupling 39 of conventional type. The opposite cooperating blades 40 of the coupling 39 are fastened to a driven shaft 4| rotatably supported by a bearing 42. The shaft 4| has a fluid inlet passage 63 leading into the coupling 33 for a purpose to be explained hereinafter. There is further provided in the fluid coupling 39 a fluid outlet port 44 through which the hydraulic fiuid may be returned from the coupling 39 to a suitable sump not shown.

Keyed to the driven shaft 4| is a high speed gear 45 which drives through gear 43 the drive shaft 47 of the supercharger 32.

The low speed coupling gear 35 drives through a shaft 48 rotatably supported by a bearing 49 one set of blades 58 of a hydraulic coupling 5| of similar type to coupling 39 and having fluid outlet ports 5 IA. The opposite cooperating blades 52 of the coupling 5! are fastened to a driven shaft 53 rotatably supported by a bearing 53A. The shaft 53 has a fluid inlet passages 54 leading into the coupling 51. The latter passage is controlled by a valve 54A of a type arranged so that when the driven shaft 53 rotates at a speed greater than the driving shaft 48 the passage 54 is closed for a purpose which will be described hereinafter. The coupling and valve may be of a type described and claimed in U. S. Patent No. 2,400,307, granted May 14, 1946 to L. S. Hobbs et al. and assigned to United Aircraft Corporation.

A conduit 56 leads from an airscoop through a carburetor 51 into the air inlet for the supercharger 32. A conduit 58 leads from the air outlet of a supercharger 32 to the intake manifold of the engine 26. A throttle valve 59 controls the air inlet conduit 56.

The throttle valve 53 is controlled by a rod 69 operably connected, as shown in Figure 2b, to a throttle control arm 6|.

The throttle control arm BI is keyed to a shaft 52 rotatably mounted in a bearing formed in the casing of the control unit as indicated at 63. Rotatably mounted in the shaft 62 is one end of the shaft 4.

There is provided a servo piston 64 for operating the throttle 59 through shaft 62. The piston 64 is slidably mounted in a cylinder 65 having fluid pressure inlet passages 56 and 51 opening at opposite sides of the piston 54.

The piston 64 has a piston rod 68 pivotally connected at one end to the piston 64 and at the opposite end pivotally connected to an operating arm 69 formed integral with the rod 82.

Keyed to the pilot's control shaft 4 is a second arm 10 connected through a link I! to one end of a walking beam 12. The opposite end of the walking beam 72 is connected through a link 73 to the arm 69.

Pivotally connected at a point intermediate the opposite ends of the walking beam 12 is one end of a lever arm 74 which is affixed at the opposite end to a shaft 15.

The shaft 15 is rotatably supported in hearing portions 16 and 71 formed apart of the control unit. Freely'rotatable on the shaft I5 is an arm 78. The arm 18 is pivotally connected at the free end to a rod 19 which connects the arm 18 to a piston 80. The latter piston is slidably mounted in a cylinder 8! into which opens at one end a passage 82 leading to a fluid pressure line such as oil under engine pressure. The piston 80 is normally forced under pressure of the oil in an upward direction as viewed in Figure 2b.

A spring 83 is positioned between the piston and the upper end of the. cylinder so as. to. force the. piston in a downward direction upon oil pressure failure, whereupon the arm 58 is forced in a clockwise direction. An adjustable screw 04 projects through the arm 18 and is arranged so as to engage an abutment plate 85. on the arm- It in the latter event so as to restrain movement of the arm I4 in a counter-clockwise direction. A stop pin 36 projects from a portion ill of the. casing of the unit so as to restrain the arm 14 from movement in an. opposite direction.

The pilots control lever may then effect manual control of the. throttle valve 59 through shaft 4, arm 10, link H, walking beam 1?, link 73, arm 69 and throttle control shaft 62 The aforenoted manual control feature is described and claimed in the copending divisional application Serial No. 12,734, filed March 3, 1948, by Howard A. Alexanderson and. Robert 2. Hague and assigned to Bendix Aviation Corporation.

The. adjustable screw 34 is preferably adjusted so as to permit a small amount of angular travel of lever M between screw 04 and stop pin 85. During such manual operation of the throttle E9,

lever arm M. is driven between its restraining stops 8A and 3's rotating shaft '15.

At the opposite end of the shaft I5 there is affixed an arm 83 through which projects an adjustable screw 89. The screw 89 is arranged to engage a pin 99] which projects from an arm 9!,

supported on shaft I5. The arm SI is freely rotatable on the shaft i5 and includes a second pin 92 which projects therefrom into a slot 53 formed in. an arm 95 freely rotatable on a pin 95 projecting from one end of a shaft Q5. shaft 96 is rotatably supported in a bearing 91 formed apart of the casing of the control unit A and the shaft 96 may be rotatably adjusted as described and claimed in the copending divisional application Serial No. 129,132 filed November 3, 1949 by Robert Z. Hague and Howard A. Alexanderson and, assigned to Bendix Aviation Corporation.

The arm 94 has an abutment plate 99 which bears upon one end of a plunger I slidably supported by bracket portions it! and biased. in an upward direction by spring I02. Lever arm 94 is driven by pin 92 of arm 9| so as to move plunger I00.

The plunger I00 is arranged so as to operably contact at I02 one end of a. valve stem I03 which is biased under force of a leaf spring WA in. an upward direction. A valve stem ill-3 has valve members 105 and E06 arranged so as to control passages and 6? respectively opening into valve chamber it? and leading to chamber 65 at opposite sides of piston 6d so as to control the movement of the piston 64. The fluid pressure line 82 opens intermediate the openings of passages t6 and iii to valve chamber I 01. A fluid medium outlet or drain passage I08 also opens from the valve chamber I0! at. the. upper and lower sides of valves I and I03, respectively.

Another valve chamber IE0 is provided separated from the valve chamber I0! by a sealing member MI. Projecting through the sealing member i I i is a valve stem I I2. At the lower end of the valve stem H2 is mounted a cylindrical valve I I3 having a spring I I4 which tends to bias the valve I I3 and stem I I2 in an upward direction.

The fluid pressure passage 02 opens into the valve chamber no at the upper side of the valve H3 so that during normal operation the fluid pressure medium forces the valve H3 downward The 6. into the position shownv in Figure 2a; The exhaust passage I08 has a port: [k5, opening into the. housing of. the control unit A and a port Iii opening into the chamber IIB, but closed by the valve I I3 when biased downward to the position shown in Figure 2a. A. main drain passage III! opens into the valve chamber H0. During. normal operation the: fluid mediumv is drained from the housing by suitable: ports not shown.

When. no pressure medium is available or upon oil pressure failure the drain valve: H3 which is loaded byspring I I4 is: moved. in an upward direction under force of the spring H4 serving twopurposes. It causes. the oil in the housing of the control unit A to drain to a predetermined low level by uncovering a. drain port I-Iliv so as to. permit such, drainage through port.- II5, passage [0.8, port. H16, valve chamber [I0 and through passage Hi! to the fluid outlet. Secondly the spring I14 urges valve stem Ii-Z. upwardinto contacting relation with the. lower end of the valve stem I03 so as to actuate the valve stem I03 in an upward direction.

During such fluid pressure failure, movement of the pilots control lever I so as to. move arm 10 in a counter-clockwise direction causes. movement in a counter-clockwise direction. of: the lever arm 14 between its restraining stops 86 and 84 whereupon valve stem IIZ under force of spring H4 causes servo valve to move from its neutral position as shown in Figure. 2a to an upper position sov as to uncover the ports leading to passages 66 and 61 soas to. permit. movement of the throttle 59 manually. Similarly upon movement of the lever arm I4 in a clockwise direction between itsv restraining stops 85 and 86 as upon manual movement of arm 10? in a clockwise direction lever arm 54' actuates through plunger M0 the valve: stem I03 in a downward direction opening the. ports. to passages 06 and 61. It will be seen from the foregoing that the manual operation of the. servo valve I03 not only permits the opening of the passage 66 and 61 so that the manual operation of arm '59 and accordingly throttle 59 may be effected, but in the event slight pressure be available such movement of the valve I03 directs such slight pressure so as: to effect piston 64 so as to assist the manual movement of the arm 58 and thereby assist in the manual control of throttle valve 59.

The latter feature of effecting manual control of the position of the throttle upon pressure. failure is described and claimed in the copending parent application Serial No. 596,472, filed May 29, 1945, by Howard A. Alexanderson and Robert Z. Hague and assigned to Bendix Aviation Corporation.

Automatic control of throttle- 'tomove free of the valve stem H2 under automatic control.

In order to effect the latter automatic control there is provided a pressure responsive bellows assembly including an evacuated bellows I2 I, sup.- ported at one end by a stud I22 carried by a portion I23 of the control unit A.

A spring I24 is positioned within the evacuated bellows I2I tending to expand the same. At the opposite end of the bellows I2I there is provided a movable plate I25 interposed between the bellows I2I and a. second bellows I26. The bellows I26 is mounted at the opposite end by a portion I21 of the control unit A. An adjustable pin I28 projects into the bellows I26 from the portion I2'I so as to limit the extent of contraction of the bellows I 26 for a purpose which will be described hereinafter.

A passage I29 formed in the control unit leads from the interior of the bellows I26 to a conduit I30, shown in Figure 2b. The conduit I30, as shown in Figure 1, leads to the air intake manifold conduit 58. Thus the bellows I26 is controlled by the intake manifold pressure of the engine 26, which in turn is affected by the position of the throttle valve 59.

The movable plate I 25 between the manifold pressure -bellows I26 and evacuated bellows I2I is connected through a link I 3I, leaf spring I32, beam I 33 and the leaf spring I04 to the servo valve I 03. Beam I 33 in the schematic drawing of Figure 2a, contains at opposite ends the preloaded leaf springs I04 and I32 which permits deflection of the servo valve I03 by plunger I and valve stem II2 without excessively loading the bellows assembly. The beam I33 may, however, be made in the form of a solid beam and link I 3I provided with a preloading mechanism which maintains the link I3I at a fixed length.

The selected pressure or datum of the bellows assembly may be changed by moving a pin I34 on which beam I33 is pivotally supported. Pin I34 is adjusted through operation of a whifiletree type of beam I35 controlled through operation of a pressure selecting mechanism, a cruise override lever; a hydraulic follow-up mechanism;

and an altitude droop mechanism as will be described hereinafter.

It will be readily seen however from the foregoing that upon an increase in the intake manifold pressure above the selected pressure there will result an expansion of the manifold pressure bellows I26 causing the beam I33 to be shifted in a clockwise direction whereupon the servo valve H13 will be adjusted upward causing a pressure medium to be applied through the passage 66 to the upper side of the piston 64 and exhausting the lower side through passage 61. This action will cause the piston 64 to be adjusted downward so as to adjust the arm 69 in a counter-clockwise direction moving valve 59 of Figure 1 through rod 60 in a valve closing direction decreasing the intake manifold pressure until the valve I03 is returned to a neutral position. An opposite efiect is of course produced upon the intake manifold pressure dropping below the selected value.

Pressure selecting mechanism As shown in Figures 2a and 3 pressure selector cam !36 is rigidly keyed to a pilot's control shaft 4. Contacting the contour of the selector cam I36 is a cam follower I31 projecting from a follower lever I33. The follower lever I38 is loaded by an extension sprin I39 and pivotally mounted on a selector plate I40 at pin MI. The selector plate 40 is pivoted on a pin I42 which projects from a portion I43 of the control unit A.

An adjusting screw I45 is mounted on the selector plate I40 and limits the clockwise rotation of lever I 38. The selector plate I40 pivoted on the pin I42 transfers adjustment-thereof to the whiflie-tree I through an interconnecting pin I46 projecting from the plate I and upon which the whifiie-tree beam I35 is pivotally mounted. It will be readily seen from the foregoing that with spring I39 pivoting lever I38 at follower I31 in a clockwise direction into contacting relation with adjustment screw I45, the follower I31 and selector plate I40 act as a unit, and the pressure selection of cam I36 is transmitted to the bellows and valve linkage through pin I46, beam I35 and pin I34.

The manifold pressure bellows I26 is provided with the adjustable lock out stop pin I28 previously described. The latter pin I28 is adjusted to a low manifold pressure value below the minimum idling pressure for the engine 26, but above the minimum selected pressure. When pressures are selected by the pilot through operation of the control lever I which are less than the lockout setting pressure, the control unit A is locked into manual operation through the joint effect of the pin I 23 and I34 causing the adjustment of the valve I03 upward tending to adjust the throttle valve 59 to a closed position. Thus through appropriate manual adjustment of the control lever I, the throttle 59 may be manually controlled, as described and claimed in the copending parent application Serial No. 596,472, filed May 29, 1945, by Howard A. Alexanderson and Robert Z. Hague and assigned to Bendix Aviation Corporation. The latter lockout feature is described and claimed broadly in U. S. Patent No. 2,453,650, granted November 9, 1948, to Howard A. Alexanderson and assigned to Bendix Aviation Corporation. The lockout stop I28 also permits closing of the throttle 59 in the event of a broken evacuated bellows, since it provides means for placing the control unit into manual operation.

Economy lever control The economy control, as described and claimed in the copending divisional application Serial No. 129,132, filed November 23, 1949, by Robert Z. Hague and Howard A. Alexanderson and assigned to Bendix Aviation Corporation, includes a pilots economy control lever as indicated in Figure 1 by the numeral I50. The latter lever I50 is connected through a rod I5I to a control arm I52 keyed to the shaft 96 previously described and shown in Figure 2a. Keyed to the shaft 96 is an arm I53 connected by link I54 to .a bell crank I55 freely rotatable on the shaft 4.

The bell crank I55 has a stud I56 projecting therefrom and arranged so that when the economy control lever I50 is rotated so as to move the arm 52 in a counter-clockwise direction to the cruise position, the economy bell crank I 55 is rotated clockwise so that during operation in the cruising range of power stud I56 will raise lever I38 increasing the selected pressure setting and stud I56 will replace follower I31 as the pivot for the lever I38.

As the pilot's control shaft 4 is rotated in a counter-clockwise direction towards closed throttle, the cruise pressure setting must be reduced at an appropriate point and the pressure setting brought down to the normal selection. In order to effect the latter operation a collar I60 is keyed to the shaft 4 having an adjustable screw ISI arranged so as to contact an end I62 of a lever I63 freely rotatable on the shaft 4 so as to limit the rotation of lever I63 in a clockwise direction. Thus as shaft 4 is rotated in a counter-clockwise direction towards closed throttle, lever I63 is moved by screw IBI at a predetermined adjusted position of the shaft i in a counterclockwise direction so as to apply a load to the selector plate I40 through a pin lfi l projecting from the plate I40. As the shaft 4 is adjusted further towards closed throttle position, the plate MI} is adjusted in a clockwise direction about the pivot pin I42 so as to .eifectively reduce the selected pressure as the control shaft is rotated towards closed throttle osition.

When economy control lever i52 is rotated clockwise to the magneto check position, stud I55 contacts an upper projection of selector plate I40, causing the selector plate Hill .to move in a clockwise direction and effectively locking the pressure selection at a low value and maintaining the throttle at its minimum position for purposes of checking the magneto.

The economy control feature is claimed broadly in the copendins application Serial No. 581,878, filed March 9, 1945, by Howard A. Alexanderson and Harold A. Wheeler and assigned to Bendix Aviation Corporation.

Altitude correction droop mechanism There is provided an altitude correction device or droop mechanism shown in Figure 2. The altitude droop mechanism serves in the single stage supercharger system disclosed (where no intercooling is provided) to prevent detonation at high altitude due to high fuel mixture temperature. At sea level a given supercharged intake manifold pressure may not cause detonation due to its relatively lower temperature, while at relatively higher altitudes the same supercharged intake manifold pressure may have a relatively igher temperature. The altitude droop mechanism reduces the selected manifold pressure with increase of altitude to within a safe operating range. Thus at high selected manifold pressures drooping in the selected intake manifold pressure is started at relatively low altitudes and the manifold pressure setting decreased rapidly with change in altitude.

As lower manifold pressures are selected, drooping in the intake manifold pressure starts at a higher altitude and occurs at a slower rate until at low manifold pressures no correction .or droop is required and constant manifold pressure control is provided.

The foregoing operation is effected through a bellows assembly including an altitude bellows Ill) opposed by an evacuated bellows I H including an internal spring I12. The bellows [10 is connected through a conduit I73 to the atmospheric or scoop pressure at the inlet .to the conduit 56 as shown in Figure 1.

The position of the plate IlII between the bellows I19 and Ill is an indication of the prevailing atmosphere. This indication is transmitted by a lever I75 pivotally supported at I16 and connected at one end to the plate I'M and at the opposite end to a plunger 11?. The plunger I'll is slidably mounted in a supporting bearing I18 and is arranged so as to actuate a cam lever I19 pivoted at one end on a fixed pivot I80 and having a plate It! at the opposite end upon which the free end of the plunger I'll bears. A spring l'tliA biases the cam lever I19 towards the plunger Ill. The spring 186A in actual practice may be in the form of a torsion spring about the pin 1%.

A second lever I82 is pivotally supported on a fixed pivot I83. At one end of the lever I82 there is provided a sleeve like bearing I184 formed intcgral therewith and spin I85 projecting through it said bearing I84 and rotatably connected at one end to the lever I82.

The opposite end of the pin I85 is affixed to a follow-up lever and transmits its motion to the selector whiflletree beam ltd through a link I81 pivotally connected at one end to the follow-up lever its and at the opposite end to the beam 135.

Lever 1.82 is spring loaded in a clockwise direction by a spring its which in actual practice may be in the form of a torsion spring about pin l8.3l The movement the lever I82 in a clockwise direction is limited by a pin IBI. The cam lever Ils transmits its motion to lever I82 through a pin it? which is formed as an integral part of a link I The pin I92 may be adjusted along the surface of the lever lie and between the levers Ila and I82 from a point coinciding with pivot pin I835 to a position at the left thereof. In the former position it pill be readily seen that since the pin I92. of link I93 would be located at the pivot I80 of the cam lever I19 that motion of the altitude bellows could not transmit any motion to lever I82. However as the pin I92 is adjusted to the left of pivot I88 correspondingly greater movement will be imparted to lever I82.

In order to effect the latter adjustment of the pin I92 the link IE3 is pivotally connected to one end of a cam follower arm I95 pivoted on a fixed pin i556 and hearing at the opposite end upon the surface of a it! keyed to the main control shaft 4 under the biasing force or a spring i-SIEA which in actual practice may be in the form of a torsion spring about the pin I96.

It will be seen from the foregoing that as the altitude correction cam it? is rotated clockwise the cam follower lever [95 is pivoted at pin I96 so as to move link I33 and accordingly pin I92 into a position where the adjustment of cam lever iii can be transmitted to lever M2. The cam shape provided at the upper surface of cam lever IlS determines the altitude at which motion will be transmitted to the lever I82 for manifold pressure setting. The shape of the cam lever is so arranged that the greater the intake manifold pressure the lower the altitude at which correction is effected and that at very low pressure settings no altitude correction is effected.

The feature of the altitude correction droop mechanism is described and claimed in the copending divisional application Serial No. 111,895, filed August 23, 1949, by Howard A. Alexanderson and Robert Z. Hague and assigned to Bendix Aviation Corporation.

Injection system Asbest shown schematically in Figure 1 there is connected to the carburetor M a conduit 2% leading. irom a suitable source of fluid fuel for the aircraft engine. There is also .provideda conduit Zili for injecting the fuel into the induction system through a nozzle 2E2. There is further provided a conduit .293 for injecting into the .induction system through nozzle 2G2 supplemental or so-ca-lled anti-knock fluid medium such as water, water alcohol or other suitable fluid well known in the art for suppressing predetonationof the engine 26.

The conduit 283 is connected to a suitable metering device shown in dotted outline and indicated generally by the numeral 2st. The latter metering device may be of a suitable type well known in the art for determining the rate'of how of the supplemental fluid.

A conduit 205 leads to themeternzgdevice 204 1 1 from a suitable source of supplemental fluid indicated by numeral 206. In the conduit 205, there is provided a pump indicated by numeral 201 driven by a suitable power means not shown. The pump 251 supplies the fluid medium under pressure to the metering device 204.

A valve 268 is provided in the conduit 235 between the pump and metering device 204 for off and on control of the supplemental fluid injection system. The control valve 208 may be of any suitable type, but is shown herein as of an electromagnet controlled type having an electrical control circuit 209 and switch 2 l i! which is preferably mounted within the aircraft cabin for convenient operation by the pilot.

Thus the supplemental fluid injection system may be placed in operation by the pilot closin the switch 2H! so as to efiect the opening of the valve 203. Conversely, the valve 208 may be closed by opening the switch 2I0. As shown in Figure 1 the latter circuit may be also closed by the adjustment of the control lever I beyond a predetermined range of for example 63 degrees at which point a switch 2IOA shunted across the switch 2 I 6 may be closed by the control lever I.

A by-pass conduit 2H and relief valve 2I2 is provided for recirculating the fluid medium from the pump outlet to the pump inlet at such times as th valve 208 is closed and the injection system is not in operation.

A conduit 2I3 is connected to the conduit 205 between the valve 208 and the metering device 204. The conduit 2I3 leads into the control unit A to a suitable pressure reset mechanism indicated in Figure 3 by the numeral 2 I 5 and to which the present application is directed.

As shown in Figure 3 the latter mechanism includes a spring loaded differential diaphragm 220 mounted between the casing portions 22I and 222 having chambers 223 and 226 formed at opposite sides of the diaphragm 22 0. The chamber 223 is open to atmosphere through a port 225 while the chamber 224 is open to the pressure,

from the fluid medium from the injection system through a port 226 into which opens the conduit 2I3 leading from the fluid injection system. Thediaphragm 223 is operably connected to a pin 221 slidably mounted in the casing portion 22I.

The pin 221 bears at one end on the diaphragm 220 and at the opposite end on a pivotally mounted arm 223 biased in an upward direction under force of a spring 236.

Pivotally connected at 228A is a plate 23 I. The plate 23I has formed therein a longitudinally extending slot 232 which opens at the lower end thereof. Positioned in the slot 232 is a cam follower I31 which projects from the follower lever I38 into the slot 232. The upper end of the follower lever I 38 is connected by the spring I39- to the arm 228 and the follower I31 is biased by the spring I39 into contacting relation with the cam I36. .As shown in Figure 3, the plate 233 is pivotally mounted on plate 23E at 234 and has suitable rack teeth 235 screw threadedly engaged by an adjustable screw member 236 so that the position of the plate 233 and accordingly a cam surface 240 provided on the plate 233 may be initially adjusted in relation to the plate 23 I. As shown in Figures 2a and 3 the sprin I39 is connected at one end to the upper end of follower I38 and at the other end to arm 228 so that the spring I39 durin normal operation tends to bias the follower I38 in a clockwise direction about the pin MI and the cam follower I31 into contacting relation with cam I36.

It will be readily seen from the foregoing that upon operation of the fluid injection system the fluid medium under pressure entering the chamber 222- will bias the diaphragm 220 downward actuating the lever 228 in a counter-clockwise direction. The latter action will cause th plate 23I to be forced downward shifting the cam surface 240 relative to the cam follower I31 slidably mounted in the slot 232.

The cam surface 240 is so arranged that upon adjustment of the control lever to within the range for operation of the fluid injection system a pin 2 H projecting from the cam I36 may contact the cam surface 243 and by appropriate adjustment of the control shaft 4 further increase the pressure setting of the unit during operation of the water injection system. The follower I38 is adjusted during the latter operation by the pin 24I acting upon the cam surface 240 so as to adjust the plate I40 in a counter-clockwise direction about the pin I42 through the follower I38 and thereby increase the pressure setting of the bellows I2I and I25.

Supercharger speed control As the valve I03 is adjusted by the bellows assembly from its neutral position there is effecteda corresponding adjustment of the piston 64 same effectively overcomes all throttle loads at a predetermined fluid or oil pressure differential of for example 20 p. s. i. When the piston 64 has opened the throttle 59 fully, if the manifold pressure still remains less than the setting, the fluid pressure differential from passage 61 to 66 will rise above the predetermined pressure value.

A metering piston-valve 250 is provided slidably mounted in a piston chamber 25I opening at one end into the chamber 55 and so arranged that the fluid pressure medium applied to the piston 84 through passage 61 may be also applied to one side of a piston head 252. The piston valve 250 includes the valve members 253 and 254 and valve stem 255 connecting the same. A passage 255 extends through the valve stem 255 and opens at opposite sides of the valve members 253. A spring 251 biases the piston-valve assembly 250 upward. A pin 256 projects downward from the valve 254 and is slidably mounted in a sleeve member 259. The member 259 is screw threadedly engaged in a portion 266 of the control unit A and is arranged so as to limit the upward movement of the piston valve 250. Mounted within the sleeve member 259 is a stem 26I having a nut portion 262 screw threadedly engaging a screw 263 locked from rotation by a portion 264 engaged in the member 229. The stem 26I is engaged at the outer end by nuts 265 so that the same may be readily locked in adjusted position. There is formed in the outer end of the stem 26I a cleft 268 for adjustment purposes.

By appropriate adjustment of the member 259 and screw 263 the limits of movement of the piston valve 252 may be readily determined.

The valves 253 and 254 are arranged to open in sequence the passages 210 and 2H to pressure medium supplied the valve 250 through pressure conduit 212 as the pressure supplied the chamber '65 through passage 61 exceeds predetermined differential values above the pressure supplied the opposite end of the valve through a passage 215,

which as will be later explained equals the pres sure in line 66.

The passage 27!] opens into a conduit 218 which as shown in Figure l supplies fluid medium to the low speed coupling through passage 5 and valve 54A. Similarly the passage 21! opens into a conduit 2i! so as to supply fluid medium to the high speed coupling 39 through passage 43.

The hydraulic couplings 5! and 39 serve to couple the driving member to the driven member 4! at varying speed ratios depending upon the rate of fluid flow supplied to the individual cou pling which thus determines the slippage of the coupling and its speed ratio.

The metering piston-valve 259 is adjustably positioned by the aforenoted differential pressure so as to properly control the coupling ratio and accordingly the driving speed of the supercharger 32 so as to maintain a preselected intake manifold pressure in the conduit 58 as controlled by the servo-valve 893. By appropriate adjustment of the members 259 and 26! the minimum opening of the low speed passage 219 and the maxi mum opening of the high speed passage 21'! may be conveniently adjusted.

In order to provide a substantially constant pressure in the passage 2'12 there is provided a reducing valve 289 including a valve chamber 28! having a pressure inlet passage 282 leading from the piston chamber 8! and opening in the chamber 28! at a point between parts 283 and 284 of the valve 289. A spring 285 biases the valve 289 in an upward direction tending to counterbalance the pressure applied at the upper end of valve valve por- 280 through a passage 286, while the tion 283 tends to open the passage 212 to the pressure medium as the valve 289 is biased upward by the spring 285 so as to increase the pressure applied through passage 286 to a predetermined constant may be adjusted by means of a suitable adjusting mechanism 28! so as to vary the maximum flow through passage 219.

The aforenoted novel arrangement of the throttle piston 94 and coupling metering pistonvalve 259 is described and claimed in the copending parent application Serial No. 596,472. filed May 25, 1945, by Howard A. Alexanderson and Robert Z. Hague and assigned to Bendix Aviation Corporation.

It has been found, however, that there is considerable variation in the back pressure in lines 2'!!! and 21! thereby causing a metering error. Novel means to correct this condition, as described and claimed in the copending divisional application Serial No. 111,896, filed August 23, 1949, by Howard A. Alexanderson and Robert Z. Hague, include a shuttle valve 290 provided to connect the pressure in the passage 210 to the lower end of the valve chamber 28! during low speed supercharger operation and the pressure in the passage 2?! to the lower end of the valve chamber 28! during high speed supercharger operation. Thus as back pressure increases the valve 289 will tend to increase the opening of the passage 212 so as to compensate for such increase.

The shuttle valve 290 is slidably mounted in a valve chamber 29i and includes a stem portion 292 having valve portions 293, 294 and 295 mounted thereon in spaced relation. A passage 299 extends longitudinally in the stem. One end of the passage 295 opens through the end of the stem 292 into the chamber 29! while the opposite end opens through the side of the stem value. The tension of spring 285 292 into the space between the valve poi-trans 294 and'295 The passage 219 opens into the valve chamber 29! at the left of the shuttle valve so that the pressure in the passage 21!] together with the force of a spring 297 biases the shuttle valve in the chamber 29! towards the right. At the opposite end of the shuttle valve 299 the pres sure passage 2T2 opens into the valve chamber so as to normally counterbalance the force ex= cited by the spring 29'! and fluid medium .from passage 2!!! and positions the valve 290 as shown in Figure 2b.

In the latter position a passage 298 leading from the lower end of the valve chamber 28!- opens into the valve chamber 29! between the valve members 294 and 295 so that the passage 210 is connected through passages 299 and 298 to the lower end of the reducing valve 289. Therefurther opens into the valve chamber 29i the passage 21! which opens at a point between valve members 293 and 294 so that in the latter adjusted position of the throttle valve the passage 21! is disconnected from the valve 280.

However, when the pressure in passage 21B exceeds a predetermined value the valve 290 is shifted to the right so as to close passage 296 to passage 298 and open passage 298 to passage 21! so as to shift the reference pressure for the fe ducing valve 280 from that in passage 210 to the pressure in passage 2! I.

After the pressure medium has been supplied through passage 2T! and 43 the high speed coupling 39 starts to over drive the low speed ecu-- pling 5 l, the low speed fluid feed line 54 is closed through operation of the rotary valve 55A permitting the coupling 5! to empty. Upon the re tary valve 54A closing the low speed pressure line 54, the pressure in passage 2'") increases to a value suihcient to cause the shifting of the shuttle valve 299 previously described and the fluid pressure in the passage 27!? maintains the shuttle valve 29!! in the latter shifted position until such time as the high speed drive operation is terminated.

If desired a separate throttling valve may be provided for each flow control port. In this way a constant differential can be provided at the metering port feeding passage 2T9 and similarly a constant pressure differential can be supplied across the port feeding passage 2? l. The throttling may be provided either by throttling the fluid medium entering the metering valve or byfeeding engine oil pressure into the metering valve and throttling the flow through passage- 210 or 21! as required.

Follow-up mechanism When valve 259 is moved from one position to another, there is an elapse of time required to flow the fluid medium into the hydraulic coupling 39 or 5! to bring the coupling to the par ticular slip condition required, and for the 811-- 302 having a valve opening 303 at the upper end.-

The valve opening 303 is controlled by a valve member 394, mounted on a stem- 395 extending This time lagl longitudinally through the passage 302 and fixedly mounted at opposite ends of the valve chamber I. There is provided a slight clearance between the defining surface of the valve opening 303 and the valve member 304 suilicient to permit a limited passage of the fluid medium or oil. The stem 305, as shown in Figure 2a, is positioned in spaced relation to the inner surface of the passage 302 so as to permit passage of the,

pressure medium such as oil upon opening of the valve opening 303.

The follow-up valve-piston 30I is centered by the action of a spring 306 which bears at one end upon an annular plate 301 slidably mounted within a portion of the valve chamber and engaging a shoulder 308 formed on the valve 30l. Movement of the plate 30! is limited by another shoulder formed within the valve chamber. The opposite end of the spring 306 bears upon a similar annular plate 309 slidably mounted within a portion of the valve chamber but similarly limited by a shoulder portion formed within the valve chamber. The plate 309 is engaged by a nut 3I0 provided at the lower end of the pistonvalve 30I. The annular plates 30'! and 308 are slidably mounted on the piston valve 30I and are biased in opposite directions into engagement with the shoulder 308 and nut 3I0, respectively.

An annular recess 3| I is formed in the pistonvalve 300 and opening into the valve chamber 300A at a point adjacent the recess is the fluid pressure passage 82. Passages 210 and 2'Ii also open into the valve chamber but are closed by the piston-valve 30I upon the same being positioned in the neutral position shown in Figure 2a.

Opening at opposite ends of the valve chamber 300A are the passages 66 and 215. The passage 66 leads from the servo valve I03 while the passage 275 leads from the lower end of the metering valve 250 as previously explained.

The amount of follow-up action effected by the mechanism 300 is determined by the speed of movement of the metering valve 250, since the quantity of fluid medium or oil flowing through the lines 66 and 215 to and from the follow-up mechanism is determined by the displacement of the metering valve 250. The follow-up pistonvalve 30I is biased to a neutral position by the action of spring 306 so that when metering valve 250 moves downward, follow-up piston-valve 30I due to the pressure acting on the lower end thereof moves upward and upon valve 250 moving upward the follow-up piston-valve 30! moves downward.

When the follow-up piston-valve 30I reaches a maximum permissible travel, the fluid medium or oil is by-passed through valve opening'303 which is opened by valve member 304.

During operation when only partial movement results, the oil is by-passed through the clearance between the surface defining the valve opening 303 and the valve member 304 allowing the follow-up piston valve 30I to be returned to a neutral position under the biasing force of spring 306.

When a great increase in the intake manifold pressure is required, the metering valve 250 will be subjected to a high pressure differential by the servo valve I03 and the metering valve will move downward rapidly causing the follow-up piston-valve 30I to move upward to its full extent. The latter action will not only open valve 303 but will also open the ports in the valve chamber 300A leading to the passages 210 and 16' 2H to the pressure medium supplied the valve chamber 300A by passage 82 so as to permit the pressure medium to be valved into the high and low speed coupling passages 210 and 2', respectively, to provide acceleration of the couplings 39 and 5|.

The follow-up action of the piston-valve 301 is transmitted by links 3I5 to follow-up lever I86. Follow-up lever I86 is pivotally supported by pin I 85 which is freely rotatable in the tubular member I84and lever I82. The follow-up lever I86 has the link I81 eccentrically connected thereto so as to transmit the motion of the follow-up lever I86 to the selector whifiletree beam I35. Thus upon the metering valve 250 moving down- Ward to increase the manifold pressure the follow-up piston valve 30I moves upward causing the follow-up lever I86 to move in a clockwise direction about the pin I85 and moving the whifiletree selector beam I35 in a counter-clockwise direction about the pin I46 so as to decrease the pressure setting. Likewise upon the metering valve 250 moving in an upward direction to decrease the manifold pressure the follow-up lever is moved so as to increase the pressure setting and thereby providing novel follow-up action for preventing instability of the control unit A.

The foregoing novel follow-up means has been described and claimed in the copending parent application Serial No. 596,472, filed May 29, 1945, by Howard A. Alexanderson and Robert Z. Hague and assigned to Bendix Aviation Corporation.

Operation It will be seen from the foregoing that there is provided a novel hydraulically operated control unit including a main control lever 3 and cruise override control lever I 52. In addition there are provided the lever 6| for controlling the carburetor throttle 59 and a pulley H for connection to the propeller governor.

Motion of the main control lever 3 operates the propeller governor pulley I'I through a linkage mechanism 5 and positions the pulley I1 mechanically to the required speed setting. At the same time a cam I36 sets the pressure controlling element I33 to the desired intake manifold pressure, while a second cam I91 sets the altitude droop mechanism I70 so as to correct for droop in such intake manifold pressure due to change in the altitude of the aircraft. Further a linkage positions the throttle 59 through operation of the throttle servo valve I03 and piston 64 to a predetermined open position.

In the automatic operating range of the unit (above the idling pressure range determined by bellows stem I26) the throttle opening will not be suflicient to provide the manifold pressure selected. Consequently the throttle actuating servo 64 automatically opens the throttle 59 further to give the selected pressure. At a given position of the main control lever 3 the pressure and engine speed will be kept constant within the limitations of altitude and the variations provided by the altitude droop mechanism I10. Thus the main control lever 3 provides correlated selection of manifold pressure and engine, speed.

The cruise override control I52 permits variation of the manifold pressure selection in the cruising range of pressures to provide maximum fuel economy for long range cruising. When the cruise override bell crank I55 is moved in a counter-clockwise direction, the pressure selection throughout the entire movement of the is set below a predetermined value.- This serves to lock the unit into manualoperation through the effect of the limit stem I28. so as to permit ground checking of magnetos and reduction of selected pressure in an emergency, where it is desired to keep engine speed selection to a high value.

The engine power control A isarranged for operation with a variable speed-supercharger drive including high and low speed hydraulic drives 39 and 5!, respectively. The engine power control provides automatic control of the drive by operation of a flow control valve 250. In maintaining automatic control of the manifold pressure when the throttle 59 reaches thewide open position, the flow controlvalve 250 is adjusted by increased hydraulic pressure so as to cause the supercharger speed to increase until the selected manifold pressureis reached.

Further the control is provided with a novel device 2 l 5 for resetting the selected intake manifold pressure upon operation of the fluid injection system controlled by the position of the pilots control lever l. Through the latter novel control dry operation may be maintained throughout a predetermined operating range of lever of for example, from to a 63 angular position of the pilots lever I. Within a second predetermined range of for-example from 63 to 72 the throttle lever closes a switch ZHJA effecting operation of the injection system. During the latter operation the intake manifold pressure setting is increased to a predetermined value which may be adjusted by adjusting the lever within the second predetermined range. However, in the event ofinjection fluid pressure or supply failure the intake manifold pressure is automatically reset to the maximum dry rating through operation of the device 2l5.

It should be further noted that when hydraulic pressure is available, the throttle ispositioned by the hydraulic servo piston 64 even in the manual range.

Thus upon manual adjustment of the shaft 4 in a counter-clockwise direction past a predetermined critical low pressure setting position, the cam 36 positions the pin |34- so that the valve stem Hi3 raised above its neutral position, while the pin me looks the bellows I26 outof operation in a pressure decreasing direction and is thus ineflective for returning the valve stem I03 to a neutral position.

The latter upward adjustment of the valve stem M3 opens port 66 to the pressure medium supplied through line 82 so that'pressure is applied to piston (is at the move piston 5i in a downward direction and actuating arm 89 in a counter-clockwise direction. Such counter-clockwise movement of arm 69 adjusts throttle arm 6| in a throttle closing direction and acts through interconnecting linkages l3, l2 and if so as to move-arm direction and thereby actuate the plunger I00 downward to return the valve stem I93 to a neutral position.

Further manual adjustment of the shaft 4 and the arm is in a counter-clockwise direction causes the arm is to be moved in a counterclockwise direction so that plunger Ice releases valve stem its whereupon leaf spring H34 raises the same so as to permit the pressure medium to be applied to the upper side of piston 64 causing further counter-clockwise movement of the arm so that the arm it once more resets the valve stem m3 to a neutral position and effects further pilots control M in a clockwise upper side tending to 18 adjustment of the throttle arm 6! in a valve closing direction.

Of course upon manual adjustment of the arm- 'iil within the automatic lock out range in a clockwise direction, there will be effected a clock- Wise movement of arm i -l past the critical neutral position causing valve stem I655 to be lowered whereupon piston 64' will actuate arm 69*in-a clockwise direction moving arm is in a counter-- clockwise direction so that'the valve stem 13 will be returned to a neutral position and thethrottle arm iii adjusted in a valve opening direction. Upon the shaft d being adjusted in a clockwise direction past the limit of the automatic lockout range, the mechanism-will once again be placed in automatic operation controlled by the pressure selector cam-l36.-

In the event of a hydraulic pressure failure the novel manually operable mechanical linkage 10, 11,12, 13 and i4 is arranged so asto provide direct manual throttle control as heretofore explained. This linkage is particularly effective at the time of starting the aircraft engine; The

manual throttle travel is sufficient to give normal power at take-off engine speed at sea level.

During normal operation of the engine the cruiseoverride control I50 will be kept at its neutral position and both pressure will be controlled and selected together by the single pilots control lever I.

Constant manifold pressure and engine speed will'be obtained at fixed pilots control lever l i positions up to critical altitude except as limited by the novel altitude droop clevice- I10 and as momentarily effected by the novel follow-up de-.

vice 398. The altitude droo mechanism serves to prevent the intake manifold pressure obtained through the control of the supercharger speed and throttle valve from exceeding values requiredfor the safe operation of the engine without liquid injection at the prevailing altitude of the aircraft, while the pressure reset device 215 resets the selected intake manifold pressure and increases the safe intake manifold pres re m t f r iven altitude during the liquid injection.

Although only one embodiment of the invention has been described and illustrated in detail,

it is to be expressly understood that the same is Various changes may benot limited thereto. made in design and arrangement of the parts illustrated, as will be apparent to those skilled in the art. For a definition of the limits of the invention, reference claims.

We claim: 1. In a boost control for regulating the induction system of an aircraft engine having operable biased into contacting relation with said cam for changing the pressure setting of the boost control upon rotation of the cam, a plate operatively con- 7 nected to said membrane andcam follower, said plate having a first member providing .a cam surface, a second member projecting fromsaid rotatable cam to engage the cam surface of said first member for changing the pressure setting of the boost control upon rotation of said cam within a predetermined maximum range during the operation of the supplemental fluid injection means, and said first member being adjusted by said membrane through said plate from an inopengine speed and manifold should be had to the appended.

erative to an operative relation with said second member in response to operation. of said supplemental fluid injection means.

2. The combination defined by claim 1 including said first member pivotally mounted on said plate, and adjustable means for varying the position of said first member relative to said plate.

3. In an aircraft internal combustion engine of the type including a carburetor for supplying a combustible mixture to said engine, operable means for injecting a supplemental fluid for suppressing predetonation of said engine, a supercharger for supplying air to the induction system of said engine, a throttle valve for controlling the induction pressure, a boost control for regulating the throttle valve, a manually 1'0- tatable shaft, a cam mounted on said shaft, a lever connected to said boost control for changing the pressure setting thereof, a cam follower carried by said lever, a spring biasing said lever and cam follower into contacting relation with said cam, and a reset mechanism for changing the pressure setting of said boost control through said lever in response to operation of said supplemental fluid injection system; said reset mechanism comprising in combination a membrane responsive to operation of said supplemental fluid injection means, a second lever operatively connected to said membrane, a spring biasin said lever to a first position during inoperation of said supplemental fluid injection means, a plate pivotally connected to the second lever and having a slot in. which said cam follower is operatively positioned, a pin carried by said rotatable cam, a cam member afiixed to said plate, said membrane biasing said second lever and cam member to a second position in response to operation of the supplemental fluid injection means, and said cam member when in said second position arranged so as to be operatively engaged by said pin to vary the pressure setting of said boost control upon adjustment of said rotatable shaft within a predetermined range.

4. For use in controlling the power output of an internal combustion engine having operable means for injecting a supplemental fluid under pressure for suppressing predetonation of said engine, and a main control member; means controlled by said main control member for regulating the intake manifold pressure of said engine, said last mentioned means comprising, in combination, a cam adapted to be positioned by said main control member, a cam follower, a selector plate to vary the setting of said regulating means and pivotally connected to said cam follower, a sprin to bias said cam follower into contacting relation with said cam and selector plate so as to vary the position of said plate in accordance with said cam, a pressure reset mechanism including a membrane responsive to the supplemental injection fluid under pressure, a reset plate operatively connected to said membrane and cam follower, said reset plate being adjusted by the membrane from a first to a second position in response to the supplemental injection fluid under pressure, and an actuator member adapted to be positioned by said main control member for operatively engaging said reset plate when in the second position for actuating said cam follower relative to said cam for varying the pressure setting of said regulating means to a value above the norma1 schedule, and an auxiliary control member to actuate said selector plate out of contacting relation with said cam follower to nullify the effect of said reset mechanism and for decreasing the pressure setting of said regulating means independently of the position of said main control member.

5. For use in controlling the power output of an internal combustion engine having operable means for injecting a supplemental fluid under pressure for suppressing predetonation of said engine, and a main control member; means controlled by said main control member for variably regulating the intake manifold pressure of said engine, said last mentioned means comprising, in combination, a cam adapted to be positioned by said main control member, a cam follower, a selector plate to vary the setting of said regulating means and pivotally connected to said cam follower, a spring to bias said cam follower into contacting relation with said cam and selector plate so as to vary the position of said plate in accordance with said cam, a pressure reset mechanism including a membrane responsive to the supplemental injection fluid under pressure, a reset plate operatively connected to said membrane and cam follower, said reset plate being adjusted by the membrane from a first to a second position in response to the supplemental injection fiuid under pressure, and'an actuator member adapted to be positioned by said main control member for operatively engaging said reset plate when in the second position for actuating said cam follower relative to said cam for varying the pressure setting of said regulating means to a value above the normal schedule, and an auxiliary control member to ac tuate said cam follower out of contacting relation with said cam for increasin the pressure setting of the regulating means independently of the position of the main control member, and means adapted to be positioned by said main control member to actuate said selector plate out of contacting relation with said cam follower for nullifying the effect of said auxiliary control member upon the main control member being adjusted to a predetermined position.

6. For use in controlling the power output of an internal combustion engine having operable means for injecting a supplemental fluid under pressure for suppressing predetonation of said engine, and a main control member; means controlled by said main control member for regulating the intake manifold pressure of said engine, said last mentioned means comprising, in combination, a cam adapted to be positioned by said main control member, a cam follower, a

selector plate to vary the setting of said regulating means and pivotally connected to said cam follower, a spring to bias said cam follower into contacting relation with said cam and selector plate so as to vary the position of said plate in accordance with a predetermined schedule, a pressure reset mechanism including a membrane responsive to the supplemental injection fluid under pressure, a reset plate operatively connected to said membrane and cam follower, said reset plate being adjusted by the membrane from a first to a second position in response to the supplemental injection fluid under pressure, and an actuator member adapted to be positioned by said main control member for operatively engaging said reset plate when in the second posi tion for actuating said cam follower relative to said cam for varying the pressure setting of said regulating means to a value above the normal schedule, an auxiliary control member movable in one direction from a normal position to actuate said selector plate out of contacting relation with said cam follower to decreasev the presI- sure setting of said regulating means to a value and "said auxiliary" control member movable in an opposite direction below the normal schedule,

from the normal position into contacting :relation with said cam follower'and toactuate said cam follower out of contacting relation with said cam to increase the pressure setting of regulating means to a value above the normal schedule.

7. Ihe combination comprising a cam having with said surface eluding means operatively connecting said main control shaft to said first and second actuating means.

9. lhe combination defined by claimv 7 in cluding means operatively connectingsaid main control shaft to said first actuating means, and

auxiliary control memberoperatively connected to said second actuating means for chesting independent operation thereof.

10. The combination comprising a cam' having a variable contour surface, a camfollower,

a plate pivotally connected to said cam follower,

spring means normally biasing said cam follower into contacting relation with said cam'surface and plate, actuating means to move said.

cam follower out of contacting relation with said surface, fluid pressure responsive means to control the mentioned actuating means, other actuatingrneans to move saidplate out of contacting relation with said follower.

ll. The combination comprising a cam havlate pivotally connected to said cam follower; o pg means normally biasing said cam follower into contacting relation with cam surface variable contour surface, a cam follower,

and plate, actuating means to move said cam follower out of contacting relation with cam surface, pressure responsive meansto control the first mentioned actuating means, and" other actuating means operablein one sense to move said cam follower out of contacting relation with said cam surface and operable in an-' other sense to move said plate out of contacting relation with said cam follower.

12. The combination comprising a cam-having variable contour surface, a main control shaft" for rotatably adjusting said cam, a cam follower, first plate pivotally connected to said camfollower, spring means normally biasing said cam follower into contacting relation with said cam surface and first plate, a bell crank adjustable in one sense to engage and to move said first plate out of contacting relation with said cam follower adjustable in an opposite senseto engage and to move said cam follower outof contacting relation with said cam, actuating means carried by said mam shaft and effective upon rotation of the main shaft within a first minimum range to move said plate out of consite sense in engaging relation with said cam follower, and said camefiective 'upon' rotation of the main shaftwithin a secondmaximum range to'move 'said' cam follower" out of engaging relation with said bell crank whilesaid bell crank remains adjusted in said opposite sense; a fluid pressure responsive membrane;- a second plate operatively connected to' said membrane and cam follower, a second plate adjustably positionedby'said'membrane from a first to a second position, and other actuatormeans operatively connected to said mainshaftand effective upon rotation of themain shaft to within a thil'ii. maximum range to operatively engage said sec end plate when in said second position for mov ing said cam follower relative to said cam.

13-. *Foruse in controlling the controlled by said main control member for regulating the intake manifold pressure-of the engine, saidregulator comprising, in combination, means operated by said main control member for varying the press re setting'of said regulator in accordance with a predetermined. schedule, an auxiliary control-member, first means actuated by movement of the auxiliary control member in one direction from normal position to increase the pressure setting of said regulator tca value above the predetermined schedule, and. second means actuated by movement of'the auxiliary control member in the opposite direction from normal position to decrease the pressure setting of said regulator to a value below the predetermined schedule while the main control member remains in set position, other means "actuated by the movement of the main control member within a predetermined 'maximumoperating range to increase the pressure setting of saidregulator to a value above the predetermined schedule, and a pressure responsive device for actuation by the injection fluid under pressure'rfor transferring said last-mentioned means'from anoperative to an inoperative relation upon a decrease in the operating pressure of'the-injection fluid below a predetermined value, and said second means operative by said auxiliary control member to nullify the effect of said last mentioned means.

14. Apparatus foroontrolling a supercharged internal combustion engine having operable means'for injecting a supplemental fluid under pressure for suppressing predetonation of said engine, comprising a main manually operated conrol member, intake manifold pressure responsive means adjusted by said'main manually operated control member in accordance with a normal schedule for automatically 'maintaining a selected enginefuel'intake pressure-a second manually operable member, :TQQELDS actuated by movement of he'second'member from a normal position to vary the'pressure' setting of regulator from the normal'schedule," and fluid pressure responsive means affected by. the injection flutd under pressure to transfer the control of said regulator from the normal-scheduleto a higher pressure schedule, and 'means'actuated by movement the second manually operable member to nullify the effect'of said fluid pressure esponsive means.--

15. In a regula ing system for induction pres sure of an aircraft engine having a throttle and operable means for injecting a supplemental fluid for suppressing predetonation of said engine; the

combination comprisingv .a :first rotatable-shaft power output of an internal combustion engine having operable" for pilot operation, a second rotatable shaft for positioning the throttle, a boost control responsive to the induction pressure of said engine for positioning the second shaft, a cam rotatable by the first shaft, a cam follower biased into contacting relation with said cam for changing the pressure setting of the boost control, a diaphragm responsive to operation of said supplemental fluid injection means, a plate operatively connected to said diaphragm and engaging said cam follower, said plate adjusted by the diaphragm from a first to a second position in response to operation of the supplemental fluid injectic-n means, and means positioned by said shaft for operatively engaging said plate when in the second position for actuating said cam follower-to vary the pressure setting of the boost control upon operation of the supplemental fluid injection means.

16. The combination defined by claim 15 including a member projecting from said cam, and a cam surface provided on said plate for engagement by said projecting member to vary the pressure setting of the boost control upon rotation of said cam during operation of the supplemental fluid injection means.

17. The combination defined by claim 15 including an auxiliary member for pilot operation, and means operative by said auxiliary member for nullifying the effect of said last mentioned engaging means.

18. Control apparatus for controlling the pressure maintained in the fuel mixture intake of a supercharged internal combustion aircraft engine in which means are provided for injecting an anti-detonant liquid into said intake under pressure, said apparatus comprising in combination, a pressure selecting means, an element responsive to engine intake pressure, motor means for controlling the intake pressure, said motor means a under joint control by said element and said pressure selecting means, adjustable means for modifying the pressure selected by the pressure selecting means, means for limiting the selected pressure range of the a pilots first manual control adjustable during flight of the aircraft, means operatively connecting said first control to said pressure selecting means, a pilots second manual control adjustable during flight of the aircraft, means operatively connecting said second control to said pressure modifying and limiting means for adjusting the modifying and limiting effects thereof, and a pressure responsive device for actuation by the injection liquid under pressure to increase the selected pressure of said pressure selecting means.

19. In a regulator for the induction system of a supercharged aircraft engine of the type including a carburetor for supplying a combustible mixture to said engine, operable means for injecting a supplemental fluid for suppressing predetonation of said engine, and said regulator including a boost control means for regulating said induction system so as to maintain the pressure thereof at a predetermined constant value, means responsive to operation of said fluid injection means for operating said boost control means so as to change said predetermined constant value from a first to a second selected value, and manually operable means for adjusting said first and second selected values; the improvement comprising adjustable means for modifying the pressure selected by the manually operable means, adjustable means for limiting the selected pressure obtainable by the manually pressure selecting means,

operable means, a pilot's manual control adjustable during flight of the aircraft, and means operatively connecting said control to said pressure modifying and limiting means for adjusting the modifying and limiting effects thereof.

20. Apparatus for controlling the intake pressure of a supercharged internal combustion engine comprising a member for actuating a throttle valve in the engine induction passage, a servomotor for operating said member, a device responsive to altitude pressure, a device responsive to the attainment of a certain pressure of a liquid injected into the engine induction passage, a manually positioned part, pressure selecting means under control by said devices and part, an element responsive to engine intake pressure and means under control by the pressure selecting means and by the element for controlling the servomotor.

21. Apparatus for controlling the intake pressure of a supercharged internal combustion engine comprising a member for actuating a throttle valve in the engine induction passage, a servomotor for operating said member, a device responsive to altitude pressure, an element responsive to engine intake pressure, a manually operable part, pressure selecting means operated by said part, means controlled by said device for modifying the action of the pressure selecting means so as to limit the obtainable pressure to a value less than can he demanded by manual operation, a second device responsive to the attainment of a certain pressure of liquid injected into the engine induction passage for nullifying the modifying action of the device first mentioned, and means under control by said element and by said pressure selecting means for controlling the servomotor.

22. The combination comprising, a cam having a variable contour surface, a cam follower, a plate pivotally connected to said cam follower, spring means normally biasing said cam follower into contacting relation with said cam surface and plate, and actuating means to move said plate out of contacting relation with said cam follower.

23. The combination comprising, a cam having a variable contour surface, a cam follower, a plate pivotally connected to said cam follower, spring means normally biasing said cam follower into contacting relation with said cam surface and plate, actuating means to move said cam follower out of contacting relation with said cam, and other actuating means to move said plate out of contacting relation with said cam follower.

24. The combination comprising, a cam having a variable contour surface, a cam follower, a plate pivotally connected to said cam follower, spring means normally biasing said cam follower into contacting relation with said cam surface and plate, actuating means to move said cam follower out of contacting relation with said cam, and other actuating means to move said cam and effective to move said plate out of contacting relation with said cam follower.

25. The combination comprising, a cam having a variable contour surface, a cam follower, a plate pivotally connected to said cam follower, spring means normally biasing said cam follower into contacting relation with said cam surface and plate, a bell crank adjustable in one sense to engage and to move said plate out of contacting relation with said cam follower and adjustable in an opposite sense to engage and to move said cam follower out of contacting relation with said cam, a shaft to move said cam, actuating means carried by said shaft and efiective upon rotation of the shaft within a first minimum range to move said plate out of contacting relation with said cam follower while said bell crank remains adjusted in said opposite sense in engaging relation with said cam follower, and said cam effective upon rotation of the shaft within a second maximum range to move said cam follower out of engaging relation with said bell crank while said bell crank remains adjusted in said opposite sense.

26. An engine control system comprising pilot operative means for selecting a desired intake manifold pressure for the engine, means for controlling the intake manifold pressure, manifold pressure responsive means for adjusting said control means so as to maintain the selected manifold pressure, said selecting means including an adjustable plate, an element amxed to the plate, an adjustable member for engaging said element so as to limit the selected pressure.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,453,653 Alexanderson Nov. 9, 1948 2,491,482 Dolza et a1 Dec. 20, 1949 2,565,482 Dolza et a1. Aug. 28, .951 

